Exhaust device for internal-combustion engines.



J. MCDOWELL.

EXHAUST DEVICEFOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED SEPT. 2,!916.

Patented Feb. 27, 1917.

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JAMES MCDOWELL, OF BROOKLYN, NEW YORK.

EXHAUST DEVICE FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Feb. 2'7, 1917.

Application filed. September 2, 1916. Serial No. 118,291.

To all whom it may concern:

Be it known that I, JAMES MCDOWELL, a citizen of the United States, residing in the borough of Brooklyn, county of Kings, city and State of New York, have invented certain new and useful Improvements in Ex haust Devices for Internal-Combustion Engines, of which the following is a specification.

My invention relates to a device or means for facilitating the exhaust of internal combustion engines and has for its object to produce a suction or reduced pressure at the exhaust exit of the engine thereby lessening the back pressure and increasing the power developed by the engine.

More particularly, the object of my invention is to provide a simple and inexpensive device which may be readily attached to the exhaust end of the muffler of the ordinary gasolene operated motor car, whereby suction may be developed for the purpose of quickly emptying the exhaust gases from the muffler and thereby increasing the power produced by the engine.

It is well known that the use of a muffler on a gasolene operated motor car, while necessary to quiet the engine exhaust, offers so much resistance to the exhausting gases that a very considerable loss of power results. In order to avoid'this loss of power, it has been quite common to insert a cutout between the exhaust port of the engine and the mufller. In ascending hills or when maximum speed is desired, it has been common to use this cut-out so as to exhaust from the engine direct into the open air. The maximum power has in this way been developed but the terrific noise due to this unmuflled exhaust has been so annoying that,- in most jurisdictions, the use of the cut-out has been prohibited by law.

My device is intended to be applied to the exhaust end of the muffler and operates in such a way as to largely neutralize, so far as cutting down the power developed is concerned, the obstruction to the gases usually encountered in the muffler while at the same time preserving the noise killing advantages of the muflier.

My invention will be better understood by referring to the drawings in which Figure 1 represents a side elevation of a conventional muffler with a preferred form of my device attached thereto, the device itself being shown part section and part elevation; Fig.

2 represents a central axial section, on an enlarged scale, of my device as shown in Fig. 1; Fig. 3 represents an end view taken from the left of Fig. 2; and Fig. 4 represents a section taken along the line 1 1 of Fig. 2.

My device comprises a central tube or pipe 1 concentrically disposed within but spaced from an outer hood 2, the forward end of which is formed as a bell 3. The tube 1 at its rear end preferably does not extend quite to the rear end of the tube or stem 1 of the hood while the forward end of tube 1 extends considerably forward of the mouth of bell 3.

Tube 1 is held within and spaced from stem 1 by four (preferably) longitudinally placed wires 5 which at one end are riveted or otherwise fixedly attached to the stem 4: while at their other end they are fixed in a clamp 6 adapted to be looked upon the tube 1 by means of the clamp screw 7. The use of this clamp enables the tube 1 to be shifted linearly as respects the hood 2. This adjustment, while not ordinarily necessary, may be found useful in order to obtain maximum efficiency with certain types of mufflers.

Tube 1 is preferably chosen of a diameter which will ust tightly fit within the exhaust exit tube (not shown) of the mufller. T0 attach the muffier, therefore, it is only necessary that this end of the tube be driven into the muffler exhaust pipe as shown dotted in Fig. 1; if a further support for the device is desired, brackets or some equivalent form of attachment may be used to connect the device directly to the frame of the car.

In operation, the car being supposed to be moving forward in the direction of arrow A, the air will be caught by the hell 3 and compressed as it passes into the space between tube 1 and stem 2. WVith this compression, the air acquires a greatly increased velocity. As the air leaves the rear end of the device and issues therefrom, a very powerful aspirating action results, causing a greatly reduced pressure at the rear end of tube 1. The exhaust gases which enter the mufller at the point B and pass therefrom through the tube 1 are therefore sucked out of the muffler with great quickness.

While the device as above described gives very satisfactory results, I find that in many cases it is desirable to pierce the tube 1, preferably just a little forward of the rear end of the bell 3 with a plurality of peripherally spaced openings formed at the ends of longitudinally disposed recess portions 9. These recesses 9 become gradually deeper from their front end to the opening 8.

The purpose of openings 8 and recesses 9 is to cause a certain amount of the air caught by the bell 3 to be forced into the tube 1 and to be mixed with the outgoing exhaust gases. This mixing of the air with the exhaust gases, thereby reducing their pressure and, to such extent, aiding the suction effect upon the muffler, causes a certain contraction of said gases and at the same time facili tates the exhaust by bodily blowing the gases out of the end of tube 1.

By sucking the gases from the muffler as above described, I not only decrease the back pressure, thereby increasing the useful work done by the engine, but I also cause a good deal of carbon which would otherwise be deposited within the engine and within the muffler to be blown therefrom;

An advantageous feature of my invention resides in the fact that, when applied to an automobile, the suction effect is roughly proportional to the speed of the automobile and of the engine. I11 other words, the device acts automatically to increase the power developed in proportion to the need for increased power.

Having described my invention, I claim:

1. In an internal combustion engine, in combination, a muffler, an exhaust pipe ex tending rearwardly therefrom, a hood surrounding but spaced from said pipe said hood having a bell shaped mouth extending nearly to the muffler and a rearwardly extending contracted stem, the exhaust pipe being perforated near the inner end of the bell shaped mouth.

2. In an internal combustion engine, in combination, a muffler, an exhaust pipe extending rearwardly therefrom, a hood surrounding but spaced from said pipe said hood having a bell shaped mouth extending nearly to the muffler and a contracted stem extending rearwardly beyond the exhaust iipe, the exhaust pipe being perforated 11 air the inner end of the bell shaped n'iouth.

In an internal combustion engine, in combination, a mufller, an exhaust pipe extending rearwardly therefrom, and a conical hood embracing said pipe with its larger end toward the muffler and its end of smaller diameter spaced from the pipe said hood being adjustable longitudinally upon the pipe.

at. In an internal combustion engine, in combination, a muffler, an exhaust pipe extending rearwardly therefrom, a clamp locked upon said pipe, a conical hood surrounding said pipe with its larger end toward the muffler, and a plurality of wires having one set of ends fixed to the clamp and their other ends fixed to the conical hood the wires serving to both position the hood longitudinally and to space the hood from the pipe.

5. In an internalcombustion engine, in combination, a muffler, an exhaust pipe extending rearwardly therefrom, a hood surrounding said pipe the hood having a. bell shaped mouth directed toward the mulller and a contracted stem spaced uniformly over a substantial part of its length from the pipe, and a plurality of wires lying between stem and pipe and serving as spacing members one set of ends of the wires being attached to the hood and the other set of ends being attached to the pipe.

6. A new article of manufacture comprising a pipe having one end adapted to be attached to the exhaust opening of a muffler, a conical hood embracing but spaced from said pipe, and connecting means between pipe and hood said means fixing hood and pipe in definite relative positions but being adjustable so as to permit said relative positions to be changed.

In testimony whereof I have hereunto set my hand.

JAMES McD OIVELL.

Copies, of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

